1. Technical Field
This invention relates to an improved pneumatic powered drive such as an air hoist using pressurized air to lift or lower a load. The lifting or lowering is controlled by fluid pressure and direction through the manifold, valve plate and operating valve which is controlled by the position of the operating valve causing alignment of various passages. The hoist including a unique air flow passage design defined by the manifold, valve plate and operating valve which when in a certain position causes lifting while in another lowering.
2. Background Information
Air hoists or like devices have been known and used for years. General air hoists are shown in U.S. Pat. Nos. 4,566,675 and 5,725,199. Air hoists, which are often referred to as winding machines, are basically hoists driven by an air motors. The air motors use air to drive a rotatable drive wheel or the like which rotates causing a chain, belt or other drive device wrapped therearound to move. Such air motors are typically operated using manual throttle valves operated by a worker by hand to actuate an air cylinder to control or direct fluid flow in the air motor. The air drives the lifting or lowering.
In U.S. Pat. No. 5,725,199 for instance, the winding machine includes a chain, a winding portion with the chain wound around its outer periphery, and an air motor for rotating the winding portion with high-pressure air supplied from an air supply source. The air motor includes a rotary air motor capable of rotating in normal and reverse directions. An air amount adjustment mechanism is also provided an includes an air supply valve, a first operation unit, and a second operation unit. The first operation is operated so as to rotate the air motor in a normal direction, thereby raising the load; while the second operation is operated so as to rotate the air motor in a reverse direction, thereby lowering the load. The result is a complex structure requiring duplicative parts and passages to accomplish bi-directional operation (that is lifting and lowering).
U.S. Pat. No. 4,566,675 similarly requires multiple, in its case three, throttle valves to perform lifting, lowering and holding. Thus, many air hoists designs exist; however, it is desirous to invent an air hoist of a simplified design which includes only one operating valve.
Objectives of the invention include providing a new pneumatic powered drive that may be used as an air hoist.
These and other objectives of the invention are obtained by the improved pneumatic powered drive of the present invention including an operating valve with an elongated interior chamber that has a plurality of intersecting valve ports. The operating valve further has a baffle slidable in the elongated chamber by a handle extending outside of the interior chamber. The pneumatic powered drive also includes a valve mount plate with a plurality of passages therein where each passage is aligned with one of the valve ports in the operating valve when the operating valve is mounted on the valve mount plate. The pneumatic powered drive also has a manifold with a plurality of channels each having-a plate end and an air motor end where each plate ends aligns with one of the passages when the valve mount plate is mounted on the manifold. The aligned plurality of passages and channels define a plurality of fluid passage one of which is an inlet fluid passage. The pneumatic powered drive also has an air motor that includes an air inlet connected to an air passage connectable the inlet fluid passage when the manifold is mounted on the air motor. The air motor also includes a plurality of motor ports where each are aligned with a different fluid passage and where the motor ports provide fluid access to a drive chamber in the air motor in which motor shaft is drivable.